Measuring the muon content of inclined air showers using AERA and the water-Cherenkov detectors of the Pierre Auger Observatory

Abstract

We present a novel approach for assessing the muon content of air showers with large zenith angles on a combined analysis of their radio emission and particle footprint. We use the radiation energy reconstructed by the Auger Engineering Radio Array (AERA) as an energy estimator and determine the muon number independently with the water-Cherenkov detector array of the Pierre Auger Observatory, deployed on a 1500 m grid. We focus our analysis on air showers with primary energy above 4 EeV to ensure full detection efficiency. Over approximately ten years of accumulated data, we identify a set of 40 high-quality events that are used in the analysis. The estimated muon contents in data are compatible with those for iron primaries as predicted by current-generation hadronic interaction models. This result can be interpreted as a deficit of muons in simulations as a lighter mass composition has been established from Xmax measurements. This muon deficit was already observed in previous analyses of the Auger Collaboration and is confirmed using hybrid events that include radio measurements for the first time.

arXiv comment10 pages, 6 figures

References in corpus (23)

• EPOS LHC : test of collective hadronization with LHC data
• Monte Carlo treatment of hadronic interactions in enhanced Pomeron scheme: I. QGSJET-II model
• The Fluorescence Detector of the Pierre Auger Observatory
• Hadronic interaction model Sibyll 2.3d and extensive air showers
• Non-linear screening effects in high energy hadronic interactions
• Muons in air showers at the Pierre Auger Observatory: Mean number in highly inclined events
• The Offline Software Framework of the Pierre Auger Observatory
• The Surface Detector System of the Pierre Auger Observatory
• Simulating radio emission from air showers with CoREAS
• Radio detection of cosmic ray air showers in the digital era
• The Muon Puzzle in cosmic-ray induced air showers and its connection to the Large Hadron Collider
• Antennas for the Detection of Radio Emission Pulses from Cosmic-Ray induced Air Showers at the Pierre Auger Observatory
• Energy Estimation of Cosmic Rays with the Engineering Radio Array of the Pierre Auger Observatory
• Measurement of the Radiation Energy in the Radio Signal of Extensive Air Showers as a Universal Estimator of Cosmic-Ray Energy
• Measurement of the fluctuations in the number of muons in extensive air showers with the Pierre Auger Observatory
• Reconstruction of inclined air showers detected with the Pierre Auger Observatory
• Advanced functionality for radio analysis in the Offline software framework of the Pierre Auger Observatory
• Simulation of Radiation Energy Release in Air Showers
• Observation of inclined EeV air showers with the radio detector of the Pierre Auger Observatory
• Prototype muon detectors for the AMIGA component of the Pierre Auger Observatory
• Enhancing the cosmic-ray mass sensitivity of air-shower arrays by combining radio and muon detectors
• The Radio Detector of the Pierre Auger Observatory -- status and expected performance
• Muon puzzle in ultra-high energy EASs according to Yakutsk array and Auger experiment data